1. Field of the Invention
The present invention is directed to a method and an apparatus for rapid screening of potential reactants, catalysts, or associated process conditions and more specifically, to methods and apparatuses for rapid combinatorial screening of potential reactants and catalysts in thin film melt polymerization reactions.
2. Discussion of Related Art
Since its introduction in 1970, combinatorial chemistry has become a popular research tool among scientists in many fields. Combinatorial screening for biological activity has been prevalent in the pharmaceutical industry for nearly twenty years and, more recently, combinatorial screening for improved catalysts for the bulk chemical industries has enjoyed increasing popularity.
There has been, however, a lag in the development of combinatorial screening for production scale reactions. One reason has been the difficulty in emulating large-scale reactions at the micro-scale typically necessary for combinatorial work. In particular, special problems can arise for reactions that are significantly dependent on mass transport rates or flow configuration. For example, removal of inhibitory by-products formed during melt polymerization may require substantial phase transfer or volatilization, both of which are difficult to reproduce on a small scale.
Furthermore, most combinatorial work to date has focused on xe2x80x9csolid phasexe2x80x9d reactions. It is known that a wide variety of organic reactions can be carried out on substrates immobilized on resins. However, a substantial number of production scale reactions are xe2x80x9cliquid phasexe2x80x9d or xe2x80x9cmixed phase,xe2x80x9d and are typically carried out in continuous flow reactor systems.
Finally, many combinatorial systems are highly complex and therefore may require significant effort and expense to be optimized for individual experiments. For many applications, it would be preferable to have a simple, compact system which would be suitable for bench-top experiments and yet enable high-throughput chemical screening utilizing a variety of reaction formats.
Early efforts in combinatorial screening of liquid phase reactions have focused on catalyst screening. Before the application of the combinatorial approach, catalyst testing was traditionally accomplished in bench scale or larger pilot plants in which feed to a continuous flow reactor was contacted with a catalyst under near steady state reaction conditions. This type of test system can be difficult to reproduce at the micro-scale typically required for combinatorial chemistry. Rapid combinatorial screening of reactants, catalysts, and associated process conditions typically requires that a large number of reactions or catalytic systems be tested simultaneously, while still providing a meaningful correlation between test results and eventual performance in a production-scale reactor.
As the demand for bulk chemicals has continued to grow, new and improved methods of producing more product with existing resources are needed to supply the market. However, the identities of additional effective reactants and catalyst systems for these processes continue to elude the industry. What are needed are new and improved methods and devices suitable for rapid screening of potential reactants, catalysts, and associated process conditions.
Accordingly The present invention is directed to methods and apparatus for rapid screening of potential reactants, catalysts, and associated process conditions. In one aspect, an exemplary embodiment of an apparatus of the present invention comprises a heating unit, a reaction substrate comprising at least one substrate reservoir, and a gas manifold to provide a flow of gas over the substrate reservoir. The apparatus may allow for real-time monitoring of the reaction.
In another aspect, an exemplary embodiment of a method of the present invention comprises the steps of providing a plurality of substrate reservoirs and introducing a reactant system at least partially embodied in a liquid into each substrate reservoir. The reactant system is rapidly heated to, and maintained at, at least one elevated temperature. A flow of inert gas is provided through a manifold above the substrate reservoirs. The reaction can be monitored in xe2x80x9creal timexe2x80x9d or rapidly cooled to stop the reaction prior to analysis.